A polymer-based optoelectronic interface for restoring light sensitivity to the retinas of blind rats is reported online in Nature Photonics this week. The findings highlight the potential for retinal implants to be made from all-organic biocompatible materials, rather than inorganic semiconductors such as silicon.

Fabio Benfenati and co-workers began by placing a retina with damaged photoreceptors (rods and cones) on a glass substrate coated with the transparent conductor indium tin oxide and P3HT, a polymer semiconductor commonly found in organic solar cells. They then demonstrated that the polymer layer, when under direct pulsed illumination, functioned as an artificial photoreceptor causing the retinal neurons to fire.

Although such repaired retinas are not yet sensitive enough to operate over the full range of daylight conditions, the researchers believe that there is significant scope for optimizing this technique in the future.